Field of the Invention
The present invention relates to an image forming apparatus which performs control to optimize adjustment processing performed within the apparatus according to an execution reservation of calibration.
Description of the Related Art
Some of recent electrophotographic method image forming apparatuses are equipped with an internal adjustment function executed at startup. The internal adjustment function is to automatically execute “cleaning of each unit in the apparatus”, “adjustment processing”, “in-apparatus density adjustment” for stabilizing output, and the like immediately after startup of the image forming apparatus. One example of the in-apparatus density adjustment is a correction unit using a patch image formed on an intermediate transfer member. The patch image is read by a sensor disposed near the intermediate transfer member, and a measurement result is reflected in various image formation conditions, such as a voltage condition and laser power, so that a maximum density and a halftone characteristic can be corrected.
The in-apparatus density adjustment is performed other occasion than the startup of the apparatus in some cases. Output characteristics of the electrophotographic method image forming apparatus varies according to a degree of use of the image forming unit or a change in an ambient environment. Thus, the in-apparatus density adjustment is automatically executed every certain number of outputs, so that an image quality can be kept at a certain level without troubling a user.
In addition, many image forming apparatuses are equipped with an “on-paper density adjustment” function for further stabilizing output of their own. The on-paper density adjustment is to read a patch image formed on a sheet by a predetermined measurement unit and reflect a read result in the above-described image formation conditions. Since the output characteristics of the image forming apparatus when actually forming an image on a sheet is reflected, when compared to the previously described in-apparatus density adjustment, output stabilization can be realized more accurately in response to a use environment of a user and a sheet type.
Generally, when a user instructs execution of calibration by himself or herself for stabilization of image quality, both of the on-paper density adjustment and the in-apparatus density adjustment are often performed in turn. First, the on-paper density adjustment is performed, and correction is performed using a measurement result of the output characteristics when an image is formed on a sheet. Then, after performing the on-paper density adjustment, the in-apparatus density adjustment is performed. This process is performed for creating a target value for the in-apparatus density adjustment to be performed every certain number of subsequent outputs.
A user who requires a certain level of accuracy for image output instructs execution of calibration by himself or herself when starting up the image forming apparatus. At that time, same processing is overlapped in the in-apparatus density adjustment included in the internal adjustment function to be executed immediately after the startup of the apparatus and in the in-apparatus density adjustment included in the calibration processing to be then executed in response to the instruction of the user. The overlap of the processing causes problems of not only generation of an unnecessary wait time from the startup of the apparatus to the completion of the calibration but also progression of toner consumption and wear and tear of the image forming unit.
As a method for solving the problems, a method is discussed for avoiding overlap of calibration execution instructions (see Japanese Patent Application Laid-Open No. 2006-212918). In Japanese Patent Application Laid-Open No. 2006-212918, a method is discussed which performs control, when instructions to execute same type calibration are overlappingly issued, not to execute the calibration latterly instructed.
However, according to the above-described conventional technique, if a user issues an instruction to execute calibration immediately after the startup of the image forming apparatus and during execution of the internal adjustment processing, the in-apparatus density adjustment included in the internal adjustment processing is performed. Then, when the calibration instructed by the user is executed, the in-apparatus density adjustment included in a series of the processing is not performed. In other words, the in-apparatus density adjustment using a measurement result of the output characteristics when an image is actually formed on a sheet is not performed. Therefore, an original image stabilization effect cannot be achieved in some cases in the above-described in-apparatus density adjustment to be performed every certain number of outputs.
Thus, the present invention is directed to realization of an image forming apparatus which can reduce a wait time and consumption of consumable products while maintaining an image quality to which a measurement result of the output characteristics when an image is actually formed on a sheet is reflected.